Motor/pump aggregate

ABSTRACT

A motor/pump aggregate ( 10 ), in particular for a servo-steering system of a motor vehicle, includes a motor/pump unit ( 14 ), and an outer housing ( 12 ) surrounding the motor/pump unit ( 14 ). The motor/pump unit ( 14 ) includes a motor unit ( 16 ) and a pump unit ( 18 ). At least one part of the motor/pump unit ( 14 ) is coupled to the outer housing ( 12 ) by means of a damping bearing.

TECHNICAL FIELD

The invention relates to a motor/pump aggregate, in particular to a motor/pump aggregate for a servo-steering system of a motor vehicle.

BACKGROUND OF THE INVENTION

In hydraulic systems, such as for example servo-steering devices used in motor vehicles, the energy providing components, in particular the motors and pumps, represent the main sources of noise, whereas the actuators of the systems only contribute a small amount to the overall noise. In a motor/pump aggregate of a servo-steering system including a motor unit and a pump unit with an outer housing surrounding the motor and pump units, in particular the outer surfaces of the outer housing emit noise to the exterior. Furthermore, in conventional motor/pump aggregates without particular sound-damping measures, the sound conducted through solids generated by the motor and pump units is passed on via the connected components into the passenger compartment and is emitted there as sound transmitted by air. The connected components can also be stimulated to natural oscillations, which in turn leads to the emission of sound transmitted by air.

In conventional motor/pump aggregates, to avoid vibrations, damping elements are arranged between the motor unit and the pump unit. However, this means a high expenditure in terms of construction technology and may lead to inaccuracy in the relative positioning and alignment of components of the motor and of the pump and also of the two components as a whole.

Thus, there is a desire for efficiently reducing the noise development in a hydraulic system with a motor/pump aggregate in a simple manner.

SUMMARY OF THE INVENTION

A motor/pump aggregate according to the invention comprises a motor/pump unit and an outer housing surrounding the motor/pump unit, the motor/pump unit including a motor unit and a pump unit, at least one part of the motor/pump unit being coupled to the outer housing by means of a damping bearing. The invention is based on the finding that the undesired emission and passing on of the noises generated by the motor/pump aggregate is best prevented in that the path of the conducting of sound through solids is interrupted or at least restrained as close as possible to the sound source. Through the invention, an acoustic uncoupling of the outer housing with respect to the motor/pump unit is achieved, so that the outer surfaces of the outer housing do not represent, or at least only represent to a small extent, emission surfaces for sound conducted through solids.

A passing of the sound conducted through solids on to vehicle components which are connected to the motor/pump aggregate can be prevented in that the damping bearing is coupled to a fastening part which is connected with the outer housing, the motor/pump aggregate being fastened in the vehicle by the fastening part.

In a first embodiment of the invention, the damping bearing comprises several damping elements disposed between the motor/pump unit and the outer housing. The damping elements are preferably constructed as plastic ribs. In this embodiment, the damping elements are substantially of parallelpiped shape. It proves to be particularly advantageous to align at least one damping element vertically and/or to align at least one damping element horizontally with respect to a longitudinal axis of the motor/pump aggregate, which defines a vertical direction. By means of the number, placing, alignment and the actual dimensions of the damping elements, the rigidity and the damping characteristics for guiding functions of the damping bearing, like the supporting of the weight forces of the components of the motor/pump unit and the supporting of acceleration moments of the motor of the motor/pump unit, can be optimized in line with specific objectives.

In a second embodiment of the invention, the damping bearing comprises an encircling damping element with respect to a longitudinal axis of the motor/pump aggregate. This damping element can seal a space between the outer housing and the motor unit from a space between the outer housing and the pump unit. In this case, the damping element undertakes the function of a dividing wall for the hydraulic fluid of the motor/pump aggregate, if for example only the pump unit is to have hydraulic fluid flowing around it.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of a motor/pump aggregate according to a first embodiment of the invention;

FIG. 2 shows a top view of the motor/pump aggregate of FIG. 1 without an upper housing part; and

FIG. 3 shows a diagrammatic side view, in section, of a motor/pump aggregate according to a second embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The motor/pump aggregate 10 shown in FIG. 1 comprises a metallic outer housing 12, which is illustrated so as to be transparent, in order to make visible the components situated therein. In the outer housing 12, a motor/pump unit 14 is housed, which is composed of a motor unit 16 and of a pump unit 18. The outer housing 12 serves to delimit a hydraulic fluid reservoir and is divided into a first housing part 20 surrounding the motor unit 16 and a second housing part 22 surrounding the pump unit 18. The housing parts 20, 22 are connected with each other by means of a fastening ring 24, which also represents the mechanical connecting site to the vehicle body.

The motor/pump unit 14 is held in the outer housing 12 by a damping bearing which is formed from several damping elements 26 and 28 arranged between the motor/pump unit 14 and the fastening ring 24 (see also FIG. 2). The damping elements 26, 28 are flat plastic ribs, substantially of parallelepiped shape, which are distributed over the outer periphery of the motor/pump unit 14 and the inner periphery of the fastening ring 24. The damping elements 26, 28 are vulcanized on the one hand to the inner periphery of the fastening ring 24 and on the other hand to a sheet metal ring 30, which is shrunk onto a connecting plate 32, on which both the motor unit 16 and also the pump unit 18 are fastened.

In relation to the illustration of FIG. 1, in which the longitudinal axis A of the motor/pump unit 14 defines a vertical direction, hereinafter the damping elements 26 are designated as vertically aligned damping elements and the damping elements 28 arranged substantially perpendicularly thereto are designated as horizontally aligned damping elements. The vertically aligned damping elements 26 are rigid with respect to axial movements of the motor/pump unit 14 (down up and movements) and in particular support the inherent weight of the motor/pump unit 14. The damping elements 26 are, however, flexible with respect to a rotation of the motor/pump unit 14 about the axis A relative to the outer housing 12. The opposite occurs with the horizontally aligned damping elements 28: these damping elements 28 are rigid with respect to a rotation, but flexible in axial direction. The damping elements 28 therefore provide for a support with respect to the acceleration and deceleration moments of the motor of the motor/pump unit 16, the motor shaft of which is aligned parallel to the axis A. As can be seen in particular in FIG. 2, in the illustrated embodiment, vertically and horizontally aligned damping elements 26 and 28, respectively, alternate in peripheral direction.

The cooperation of all damping elements 26, 28 provides as a whole for a damped, vibration-equalizing bearing of the motor/pump unit 14 in the outer housing 12. The damping elements 26, 28 separate the motor and the pump as noise sources from the emitting outer surfaces of the outer housing 12.

In the embodiment shown in FIG. 3, the motor/pump unit 14 is held by means of a diagrammatically illustrated, encircling damping element 34. The encircling damping element 34 can be constructed so that it is impermeable to the hydraulic fluid surrounding the pump unit 18. In this case, the space between the lower housing part 20 and the motor unit 16 is kept free of hydraulic fluid. The damping element 34 can, however, also be arranged or constructed so that it is permeable to the hydraulic fluid. This is suitable when the motor is a wet-running motor and a cooling of the motor unit 16 by the hydraulic fluid is desired.

The damping bearings described above are also advantageous for motor/pump aggregates in which the motor unit and the pump unit are connected with each other by an intermediate housing. In this case, the damping bearing is coupled to the intermediate housing. Therefore, with only one damping bearing the entire motor/pump unit can likewise be uncoupled from the outer housing, so that the excitations of sound conducted through solids of the individual components, in particular of the motor unit and of the pump unit, do not need to be damped separately. In other embodiments of the motor/pump aggregate, however, also several damping bearings can be provided, for example a bearing for the motor unit and a separate bearing for the pump unit. 

1. A motor/pump aggregate comprising a motor/pump unit (14) and an outer housing (12) surrounding the motor/pump unit (14), the motor/pump unit (14) including a motor unit (16) and a pump unit (18), at least one part of the motor/pump unit (14) being coupled to the outer housing (12) by a damping bearing.
 2. The motor/pump aggregate according to claim 1, wherein the damping bearing is coupled to a fastening part which is connected to the outer housing (12), the motor/pump aggregate (10) being fastened in the vehicle by the fastening part.
 3. The motor/pump aggregate according to claim 2, wherein the outer housing (12) comprises a first housing part (20) surrounding the motor unit (16) and a second housing part (22) surrounding the pump unit (18), the fastening part including a fastening ring (30) arranged between the two housing parts (20, 22), the fastening ring (30) securely connecting the housing parts (20, 22).
 4. The motor/pump aggregate according to claim 1, wherein the damping bearing comprises several damping elements (26, 28) disposed between the motor/pump unit (14) and the outer housing (12).
 5. The motor/pump aggregate according to claim 4, wherein the damping elements (26, 28) are constructed as plastic ribs.
 6. The motor/pump aggregate according to claim 5, wherein the plastic ribs are vulcanized to a sheet metal ring (30), which is shrunk onto a connecting plate (32) on which the motor unit (16) and the pump unit (18) are fastened.
 7. The motor/pump aggregate according to claim 3, wherein the damping bearing comprises several damping elements (26, 28), disposed between the motor/pump unit (14) and the outer housing (12), constructed as plastic ribs and the plastic ribs being vulcanized to the fastening ring (24).
 8. The motor/pump aggregate according to claim 7, wherein the plastic ribs are vulcanized to a sheet metal ring (30), which is shrunk onto a connecting plate (32) on which the motor unit (16) and the pump unit (18) are fastened.
 9. The motor/pump aggregate according to claims 4, wherein the damping elements (26, 28) are substantially of parallelpiped shape.
 10. The motor/pump aggregate according to claim 9, wherein with respect to a longitudinal axis A of the motor/pump aggregate (10), which defines a vertical direction, at least one damping element (26) is aligned vertically.
 11. The motor/pump aggregate according to claim 9, wherein with respect to a longitudinal axis A of the motor/pump aggregate (10), which defines a vertical direction, at least one damping element (28) is aligned horizontally.
 12. The motor/pump aggregate according to claims 9, wherein the damping elements (26, 28) have different orientations.
 13. The motor/pump aggregate according to claim 12, wherein at least two damping elements (26, 28) are provided, which are aligned substantially perpendicularly to each other.
 14. The motor/pump aggregate according to claim 1, wherein the damping bearing comprises an encircling damping element (34) with respect to a longitudinal axis A of the motor/pump aggregate (10).
 15. The motor/pump aggregate according to claim 14, wherein the damping element (34) seals a space between the outer housing (12) and the motor unit (16) from a space between the outer housing (12) and the pump unit (18). 